Arms race fears as last US-Russia nuclear pact expires after over half a century

Putin had indicated a willingness to maintain the treaty's limits for an additional year

U.S. President Donald Trump greets Russian President Vladimir Putin, Aug. 15, 2025, at Joint Base Elmendorf-Richardson, Alaska. (AP Photo/Julia Demaree Nikhinson, File) (Copyright 2025 The Associated Press. All rights reserved.)

The world's last major nuclear arms control treaty, New START, officially lapsed on Thursday, leaving the two largest atomic arsenals, those of Russia and the United States, without any limits for the first time in over 50 years. This development has ignited concerns about a potential unconstrained nuclear arms race.

Last year, Russian President Vladimir Putin had indicated a willingness to maintain the treaty's limits for an additional year, provided Washington agreed. However, Donald Trump remained undecided on its extension.

Kremlin adviser Yuri Ushakov stated that Mr Putin discussed the treaty's expiry with Chinese leader Xi Jinping on Wednesday, noting a lack of response from Washington regarding his proposed extension.

Russia “will act in a balanced and responsible manner based on thorough analysis of the security situation,” Ushakov said.

Russia's Foreign Ministry on Wednesday night said in a statement that “under the current circumstances, we assume that the parties to the New START Treaty are no longer bound by any obligations or symmetrical declarations within the context of the Treaty, including its core provisions, and are fundamentally free to choose their next steps.”

This photo taken from a video distributed on Dec. 9, 2020 by the Russian Defense Ministry Press Service, shows a rocket launch as part of a ground-based intercontinental ballistic missile test at the Plesetsk facility in northwestern Russia. (Russian Defense Ministry Press Service via AP, File) (Russian Defense Ministry Press Service)

New START, signed in 2010 by then-President Barack Obama and his Russian counterpart, Dmitry Medvedev, restricted each side to no more than 1,550 nuclear warheads on no more than 700 missiles and bombers — deployed and ready for use. It was originally supposed to expire in 2021 but was extended for five more years.

The pact envisioned sweeping on-site inspections to verify compliance, although they stopped in 2020 because of the COVID-19 pandemic and never resumed.

In February 2023, Putin suspended Moscow’s participation, saying Russia couldn’t allow U.S. inspections of its nuclear sites at a time when Washington and its NATO allies have openly declared Moscow’s defeat in Ukraine as their goal. At the same time, the Kremlin emphasized it wasn’t withdrawing from the pact altogether, pledging to respect its caps on nuclear weapons.

In offering in September to abide by New START’s limits for a year to buy time for both sides to negotiate a successor agreement, Putin said the pact’s expiration would be destabilizing and could fuel nuclear proliferation.

New START followed a long succession of U.S.-Russian nuclear arms reduction pacts. Those have been terminated, as well.